Can too much insulin cause swelling of the feet and legs? I take 60 units a day?

Yes it can. Do a search online. I am experiencing this myself right now. Like you I take very high doses of insulin and swelling of my feet has been really bad. This side effects doesn't seem to be common knowledge but known to be true. Its because of the effects of insulin on the kidneys.

The other thing is, if your blood sugar isn't going low you aren't talking too much insulin.

No, this is not the cause of your swelling. If your swelling is mild, watch your sodium (salt) intake from all sources, not just table salt, Salt is found in many foods we wouldnt expect like soft drinks, cereals, condiments, canned goods and frozen prepared foods. Drink more water to help flush away the retained fluid. If the swelling is pretty substantial and/or if it "pits"-press down on the top of your foot, if a finger print "pit" remains, that is pitting edema-this may indicate your heart is not pumping as good as it should and you need to see your Dr asap.