well... my antec 902 isn't built for that h100 either (it has a 200mm fan mounted on the top, and no mounts for a 240mm radiator), but the price was right ($50) so i decided to make a project of it. A bottle of superglue, and some velcro tape i bought from walmart ($5.50 total) later and i had my h100 mounted to the top of my case. That velcro works great, no drilling needed. and it clears the ram just fine.
long story short, i suspect you could mount it if you found such a deal
as for finding killer deals. it's a lot easier if you simply wait until they come up. up until i found that h100, i wasn't even planning to get a new CPU cooler. My 1080p 23" monitor was found on craigslist for $60 (pure chance that one; I was looking for a 1080p monitor for 3 months... my budget was $80; and had given up that same day and was going to get a 1600x900 monitor for $80 later that day. I checked craigslist one last time before going back to the merchant to get it, and found that monitor posted, had it in my hands 3 hours later)