So I'm not even finished with my 2 case euro-rack modular and I already have seen some frac-rack format modules that "I absolutely must have".
Of course, once the euro-rack is finished, that might turn out to be a gross exaggeration, but as of right now that's where it stands. The modules also do not have a direct euro-rack equivalent, so that makes them all the more covet-worthy. Luckily I have not found more than 1 "frac rack" of modules that I would like, so I wouldn't be sinking a bunch of money into it like I have with the euro-rack. That's at least comforting as well as the fact that the rack/PSU for the frac format is *much* cheaper than it's euro-rack equivalent (although to be honest, looks more bulky and "janky" than the Doepfer cases).
The module that caught my eye the most was the Blacet Miniwave. Thanks to zerosum's many demos, it's the one that I'd happily buy the frac format case just to have this module. It's essentially a wave-rom lookup module but can achieve many things because of this. Quantizer, Oscillator, Fuzz, Wacky-ass-control-voltage-source, etc. There's also additional ROMs that can be purchases and each wave form is CV selectable in the bank. The only thing that comes close to this on euro that I know of is the Doepfer A-112 Wavetable Sampler/OSC and it doesn't seem anywhere near as versatile.
Secondly, the Blacet Binary Zone is a voltage pattern generator. It also has on-board lag processing and accepts internal clock. It makes some rad sounding control voltages and the only way that I can explain is it is to have you check out that product page and listen to the demos. I might be able to cook up something similar with several of my planned euro modules, but why not have one module that serves the same purpose. I love tempo-accurate random stuff so this is basically right up my alley.
The third module is the Wiard Noise Ring. This module is essentially a random voltage generator (ie sample + hold), however, it has logic to govern the frequency of drastic changes and how drastic the change is. Think of it as a more musical sample+hold. I think this would be a very interesting complement to my Plan B Model 24 (Heisenberg) as I consider it a very "musical" sample+hold.
There are also other interesting offerings particularly the Borg and Boogie filters from Wiard. These look cool and would certainly fill out the extra spaces of a frac chassis, but I'm most interested in the main three that I listed. I'm not one of those guys who needs every kind of variation of filter or oscillator, but I don't think I can pass up the unique functionality of the MiniWave, Binary Zone, and the Noise Ring. I also *REALLY* like the Wiard Woggle Bug, but that is not made in the frac format. As much as I want one, I can't justify investing in a 3rd format just for that...sure there are other rad 300 modules, but I'll just be carried away to the poor house; albeit with a fine soundtrack ;)
Either way, it's a long way out...both in time and money.