Is there anyhting special about 30 min. epoxy from my LHS?
Is there something equal, or better that I can get more easily at Lowes or Home Depot?

Nope, nothing special about hobby shop epoxy.

here in Aus we can get epoxy in 5, 30, 60, and over night (12 - 24 hours) all at the local hardware although most only carry 5 and 30.

I get West System epoxy by the quarts for fiberglass boat work and it is great stuff. The mix ratio is 4:1, which makes it difficult in small batches, and it takes a good six hours to harden up. (Unless you leave it in the cup, and then it will cook off in 15 minutes with alarming heat and activity.) It also dries harder (less flexible) than the 30 minute 1:1 'hobby' brands I have used.

The good 'ol Devcon hardware store epoxies work fine. Probably cost more per ounce than what your local hobby shop has on the shelf.

My personal favorite is Hangar 9's 6 minute epoxy. I use it for most everything. Around here its 9.99 for the two bottle pack (1 bottle epoxy, & 1 bottle hardener). Lowes and Home depot cant beat it and its easier to get a little more hardener in your mix if needed.