Epoxy it and forget about it. If you buy a one way diff for the front, the diff you replace it with can always be a spare.
I normally try to go with rims with thicker spokes i.e 5 spokes etc. Just as going sideways means the wheel face takes a bit more stress and you crack rims quicker.
So try to find something that looks like it has strength to it.
shops we have..
hobbyking.com - tonnes of cheap rims and tyres, but sometimes import fees.
ebay.co.uk - duuuh! but has some of the best stuff and will be best bet for some of the harder and rare, more expensive drift stuff
rcgeeks.co.uk - normally has a nice selection of drift stuff, started as an ebay shop
maxspeedtechnology.co.uk - never used but have a nice selection
wheelspinmodels.co.uk - decent and trusted seller
jespares.co.uk - as above
cmldistribution.co.uk - as above
asiatees.com - import fees, never used, has amazing selection of rarer parts (tho maybe too good to be true)
modelsport.co.uk - great supplier and has a great selection of rims and tyres.