Just back from San An, but no riding for me. Loads of the moped hire places had adult bikes but never saw any with kids bikes. Did pass a bike shop (closed) with Spesh S-works in the window that advertised hire but not sure what.
I did look at these guys before I went but decided just to have a lazy holiday
http://www.ibizamtb.com/index_eng.html
Bear in mind it’s now low season and lots of places are closing down, but that also means there were bargin prices about on car hire etc. We had temps of 25-29 with a nice breeze to take the edge off. Enjoy.