Thank you so much for showing an interest, it means a lot.
I don't really know if that's feasible to set a budget, seeing as things cost a lot more over here in Norway than anywhere else, with the possible exception of Switzerland. Besides, I won't be buying everything at once but rather spread the purchases over time to afford it it all. In any case, once I've decided and am committed, I'll pay what it costs to see it through. Even it that gets me committed... :p
A 23' production boat which ticks most of the boxes for me with a 250HP Suzuki 4-stroke costs NOK1.1 million/USD132,000. The boxes it doesn't tick are light weight and fuel efficient - it weighs 4500kg and reaches 32 knots at WOT with said motor. They refuse to give me consumption numbers, which usually is a bad sign. The outboard alone with remote control, tacho and tilt meters, no trottle/gear cables, costs NOK260,000/USD32,000.
So.. I don't know. Is USD100,000 finished, on the water a realistic budget for a self built boat?
The outboard(s) will obviously be the single largest expense, but I'm not adverse to buying used provided the service history is good and the outboards are in good working order. I would prefer to get new ones, but buying new is... well, very expensive. I see twin outboards pop up for sale every now and then which look like good deals. No idea how it compares to the US, but here are some examples:
In August I found a pair of 2004 Yamaha 250s for sale for NOK83,000/USD9,950 for the pair, all cables and instruments included, as well as a binnacle remote control. Serviced at the dealership every year, 450-ish hours on them and were sold by the dealership for the customer with complete service booklet and 6 month warranty. I think they were 4-strokes, but can't really remember. The listing disappeared rather quickly...
In October a pair of 2017 Yamaha F350 4-strokes with all instruments popped up for NOK250,000/USD30,000 for the pair - 70 hours on both motors, recently serviced. List price of one is NOK370,000/USD44,500. These sold the same day the ad was posted.
I realize many of the designs I've looked at are old, and I'm guessing you're referring to the Hankinson designs. I don't know when he designed his power cats, but I found a build thread for the Wildcat E-X-T dated back in 1999, so I'm guessing it's at least 30 years old by now. I don't have any experience with building ply on frame, so I can't say anything about the build method (which is why I started my Build methods thread).
I really like the clean, straight lines on his cats and the walkaround cockpit. If I could get that in S&G plywood composite like you have designed your CT22, I would be a happy camper. I would love to build a CT22, but the immovable beam under the front bench bothers me - I would like a much smaller front deck (about half the size of how it's rendered), a rear-facing bench taking up the space left, and the designed bench I'd like removed completely. And I want the bow pointing forwards from the stems of the amas, not inwards. But that's easy enough to do while building.
I did a layer-on-layer drawing of the Glen-L Party Boat and the CT22 as they are the same length and width; this is the result:
It uses the CT22 hull, the Party Boat's interior with some modifications. In front of the consoles there would be a split windscreen and a sliding door to close the pathway. I'd also have some kind of bars with a rigid or soft top to get out of the rain. There isn't a head drawn, that will be a bit of a headache to place with a layout like that, but shouldn't be impossible. I haven't shown the side view, but I would like a broken sheer line because I prefer that look, maybe something like the CS25 or the Bluejacket 24. I love the flair on the CS25's bow and would love to incorporate that as well, but I'm not sure if that would flow correctly. I'd also like slightly straighter stems and sterns like on the WildCat E-X-T Sport, but that too, I guess, can be done when building.
The hull (center section/bridge deck) was widened by 3". Now that I have an accurate measurement of my mooring berth's width, I wonder if the beam could be widened to 9' to give a bit of extra room.
There is storage in all seats and benches. Under the bow seats there will be a double floor where more stuff can be stored. Fuel tanks and bilge pumps also live down there. The head could possibly be fitted under one of the rearmost bow seats with a curtain or something for an illusion of privacy.
At least that's my fantasy... but, since the forward connecting beam can't be moved, this probably won't happen. And that was the sole reason I started actually looking at the Hankinson cats. That said, should you consider a re-do of the CT22 and that re-do happens to fall in line with what I just wrote, I would no longer have any reason not to buy the plans and build the boat...