Here's the complete list:
Signed: 103, 104, 131, 260 (but some have been removed since initial signing), 273 (just 2 shields), 281, 282, 293, 331 (2 shields on side rds), 380 (1 shield at jct), 402, 422, 501, 528, 551, 569
Unsigned but should be signed: 130 (although it is on the state hwy map),
153, 154, 164, 173, 180, 194, 200,
225, 241, 255, 332, 334, 335, 350 (on state hwy map),
351, 361, 370, 410, 540 (on state hwy map), 542
Probably will never be signed: 120 (ODOT relinquished the Swift Hwy in 2007),
141 (most of route not state-maintained),
182 (relinquished),
222 (it's 2 disconnected pieces and part has been relinquished),
250, 251 (both very short),
339 (just parallels OR 11 a mile west, part not state-maintained),
413, 414 (I'll be surprised if these turn up: 414 really short, 413 is gravel for half its length),
429 (really short),
451 (doesn't really go anywhere),
452, 453, 454 (all three short, don't connect to anything in Idaho)
I agree with Bickendan on not getting hopes up; there seems to be little enthusiasm on a lot of these. I've seen projects come and go on many of these routes with no signage resulting. It seems to be a regional thing: some areas embraced their routes, like 402, 103/104 and 281/282. Some were signed right away without a lot of enthusiasm, like 501, 273, and 293. Other areas just don't seem interested despite the fact their routes would be pretty useful, like 361 and 370 in central Oregon and 540/542 near Coos Bay.