I'm using a fotek 40amp ssr and only paid $7.00 or so shipped from china. I can't find the 40 amp ones that cheap anymore though. Here's a 25amp ssr like I have which might be fine with what you're doing depending on wattage of heaters and how many heaters etc.http://www.ebay.com/itm/SSR-25-DA-Solid-State-Relay-PID-Temperature-Controller-25A-Output-24V-380V-/271092328688?_trksid=p2045573.m2102&_trkparms=aid%3D555001%26algo%3DPW.CURRENT%26ao%3D1%26asc%3D146%26meid%3D6411926506775367794%26pid%3D100034%26prg%3D1079%26rk%3D1%26sd%3D390195438437%26
I'm using halogen lamps but you can use different kinds of heating elements. I actually created a forum for DIY BGA guys but its not limited to that. Anything with heating elements and even more is welcome. Not much activity so far but people do check.
diybga.com
I'm even farther with it now but here's a video but not explained very well.
Cheers

Will post in showcase after I get my machine done. I just googled arduino rework station and this was first result so I wanted to update. Pretty amazing really, as there are plenty of other people with similar projects.