Can anyone recommend a reliable locksmith or key shop to duplicate keys in the Silom or Siam area? Thanks for any information.

There is a guy standing outside of Milk Plus on Silom, at the corner of Soi 19.

Also, there is often a key cutter/shoe repair counter at the ground floor, rear entrance to major shopping malls such as Silom Complex. (south side of Silom Rd., connected to Saladaeng BTS Station by a pedestrian bridge.) Check there if you think the outdoor guy's prices are too cheap for you.

Not to hijack the thread but a friend was just asking me where to get a key made (from Sweden) because the shops he has gone to don't have the key blank for his key. Anybody know of a big key shop or even a small one that would be smart or wiling enough to find a similar key blank that would work?

those locksmiths can be found on almost each corner, near bts, 7-11 shops, can't see any problem finding one just walk a little bit.

^ spot on advice