You mention comparisons -- if you're trying to do controlled comparisons of one mic or one mic/preamp combo to another, you might want something like the Edirol R44 (either stock, oade-, or busman-modded), or newer Tascam DR680 (stock or busman-modded).
If you're just wanting a second rig that you can run and decide later whether you like that second rig compared to your 140>v3 rig, then maybe consider the marantz pmd-661 or tascam hd-p2, both of which have a digi-coax in. I've got the sony D50 and love it. If you're V3 is opti-modded (or if you don't mind sending it to grace for the optical output), the D50 works great as a digi-in recorder with the V3, so you could switch around what you're thinking and do 140>V3>D50 and 184>?>sbm1>722.
Also, A/D stages of recorders have come a long way in the last 10-15 years, so you might consider skipping the modsbm1, and run 24 bits right into a recorder. I actually like the D50 A/D stage quite a bit and it can sound very nice just with an analog preamp in front of it. I run a transformer EAA PSP2 into my D50 all the time and like it quite a bit.
Whether or not you keep the sbm1 in the chain, you might consider the Naiant littlebox preamp with the optional transformer output. I ran a controlled comp of milab vm44-link mics split to my PSP2 and to my output-transformer modded littlebox, all into a Tascam 680. I preferred the PSP2 over the tranfo littlebox, but only by a very slight amount. Both sounded very similar, but the PSP2 seemed a bit more coherent. I need to listen more, but it may be that the PSP2 has just a bit more output in the upper-bass or lower-mids, which seems to pull together the recording a bit. Still though, the much cheaper and way easier to purchase tranfo littlebox sounded very, very good.