Thank you. It really, honestly is hard on our tech because they feel the pressure from all sides. Eight hours sounds rough for a reimage. I think ours are... maybe two or three? We've done a lot of work to get the reimage time down, and Win7 (WIMs) have made this really nice.
If this is something that smells of a bigger problem (or has been seen elsewhere) then I push for them to get the user a wholly new machine, capturing the old one for analysis. If the user is given an upgraded machine, then there is usually little resistance, even with the downtime that'll be incurred.
On the upside, if the issue can be reproduced readily, from this we can almost always get root cause and put a systemic fix in place. If it's sporadic... Well... I'm sure you understand how it goes trying to fix something that you can't yet reproduce. ;)
(I'd love to troubleshoot your slow data backup issue... That's the stuff I rather enjoy.)