The 3000/3500 were replaced by the 3100/3700 and again it was a fairly significant up grade in native contrast. The 5030 would be a good choice, not as bright as the 3100/3700 but much better contrast and they also have the greatest amount of lens shift +/- 96% compared to +/- 60% for the 3100. But again buying used is a big gamble as a lot can go wrong with these older LCD's that can't be economically fixed. For that kind of investment I would still go for the $800 3100 from Epson with full warranty.
"Smart enough to know better, to old to care" ------ Dedicated Bat Cave Home Theater, JVC RS49U/Mitsubishi HC7900DW Projector, 110" 16:9 Jamestown screen with variable power masking for CIW 2.50:1 to 16:9, Marantz 7009 with 7.1.4 Atmos with Ohm mains,3 DIY Subs (2 15" (1 ported, 1 sealed and a 12" 4th order bandpass), 1 DIY butt kicker, Custom Built HTPC, 18TB DroboFS NAS