I guess I should get out more seeing as how a compilation of Irem Arcade games flew right under my nose.
Irem Arcade Hits is a pack of 18 great to terrible games for the PC. Yes I know I say arcade and PC and everyone says "well I'll just stick with MAME then" in response. Still while the set has some kinks that need working out it's a pretty swell deal for $10 and some patches are in the works. I figure I'll give it a go and post some impressions in the near future. At least this is a serviceable explanation as to why there's been a whole lot of nothing about Irem re-releasing their library of classics.
Read more about the compilation over here.
A shmups forum thread where somebody has already purchased it and posted their impressions.