@golddrone I have Zadar and it's very extensive and a bit limited at the same time. You can't design your own envelopes like with an ADSR or a Maths. That said, there's a wide choice of envelopes in Zadar to chose from, including traditional ADSR-like envelopes. And you can bend and deform these to match more what you're looking for. For me, it is my main envelope, but I also have a basic AR from Doepfer which works very well for several sounds. I also don't recommend only Zadar. And despite not really getting the Maths hype for half a year, I'm very much planning to get one now. It's just so versatile!
@JimHowell1970 I've been thinking about your comments on the 1U for a while now. I'm not discounting utilities as "not real" or "not full". But a multiple, when patched, there's just no wiggling to it. So having those out of the way centrally (my 1U is in the middle) makes a lot of sense. Aside from the Quadratt, I also like the switched multiple. Both can be set up so that there's plenty of room for wires passing along them while still being easily reachable while playing. So overall, I'm not unhappy with it in the way that I use it now - superhighway for cables with a few useful modules that I can still reach.
On the other hand, I like your alternatives to 1U, like the 3x MIA, a lot. There's obviously much more choice in 3U than the handful of useful modules in 1U. I've been really looking hard at sensible ways of filling up that 1U space and it's just not easy to do it with useful modules that compare well to 3U alternatives. So when designing a DIY rack, I'll most likely not have a 1U rail. I'll keep the Intellijel as well as the 1U modules because even if the new rack would be 600hp, I know I'll run out eventually
As for the price of the rails - well. Compared to the price of an off-the-shelf rack, it's going to be small change anyway...