I think I'll discard the unchewed bullet and stick it out until I build the new system as-is. I'm technically able to run all 3x 2560x1440 monitors w/ the 5750 running one through display port and a D3100 dock running the other 2, but the 2nd monitor through the dock is only running at 50 Hz and it's killing me. Some people say it shouldn't be perceptible ( some programmers even claim to work on a 30Hz 4k setup, wtf? ) but to me it's completely palpable w/ the cursor tracking and keyboard input appearing. I'm going to hunt down a dual-link DVI cable and see if the 5750 can't power 2 at 60Hz.
But then as soon as the new procs and mobos are out, it's upgrade time.
For the record, the 14 core Precision actually felt less responsive than this t110.2. It was very noticeable for me. So SCREW any processor w/ a baseline speed of less than 3.3.
Again, thanks everyone for your help and input on this. @MattSpeller, I'll definitely be spamming you for advice and insight as I dig into the puzzle of jaw-dropping performance on a budget.