No Problem what so ever, did you already have the Sleds? I have got the machine that came both ways some with them and some without, but they are cheap on eBay if needed.
Next thing I want to try; I got old 200gig Seagate HDs at work the other day on a pull-off job, I am going to look up the specs and see if I can get them to work in a 550, I know I will only get 130'ish GBs of use, for for the low low cost of nothing, what do I have to lose.
If they have a jumper for LBA24 I think they might just work!