I'd love to get my hands on a surplussed M110, to go with my M24R. Then I'd just need an M107 to make my family complete!
But, I wouldn't hold my breath. The politics of allowing those into civilian hands just don't seem to make it sound all that likely. IMO, about the only chance would be if KAC were able to buy them back, or if HK took them in on trade to reduce the per-unit cost. Neither seems all that likely. KAC prob doesn't want to heavily advertise that their product barely lasted 10 years before being replaced... and I doubt HK has any interest at all in off-loading a bunch of non-HK rifles.
End of the day, the M110's will likely to go other countries, and LE through the 1033 program.
As far as the M110A1 in the Corps- it's there to serve the same purpose it serves with Army snipers; mid-range and urban sniper engagements... and as a sniper support weapon. The Corps will end up with a .300 or .338 sooner or later. Despite just going through another round of upgrades, I don't think the M40 is too much longer for this world.