Offhand I actually don't know of too many DAW programs that can record the individual tracks in FLAC format. Reaper does. Checking the Wiki (https://en.wikipedia.org/wiki/List_of_hardware_and_software_...), it looks like Cakewalk Sonar does as well. But that leaves a lot of major players (Protools, Logic, Cubase, Ableton Live, FL Studio, etc.) that cannot.

It's not something I personally would do because (as others imply) IMHO the CPU trade-off is not worth it. Usually I use a blend of plug-ins (which take up no space) and recorded hardware, consequently the amount per track ends up being more like 100-600MB and not gigabytes. This is rather manageable.

However, I will note that sample based software synthesizers and sample packs can be huge these days, even despite in many cases lossless compressing being applied to the sample library. Omnisphere 2 for instance comes with a 60GB+ sample library (and that's before you add the add-ons like Moog Tribute). At the current extreme end, orchestral sample company Spitfire offers a string library (https://www.spitfireaudio.com/shop/a-z/hans-zimmer-strings/) that is 183GB in size and a sampled piano that's a whopping 211GB compressed (https://www.spitfireaudio.com/shop/a-z/hans-zimmer-piano/).