I just recently got a mini pel. from a herb nursery, with tiny pink flowers and leaves all over. It looks just like a little bonsai (woody), and I love it! Don't have the name at hand, but I'm sure if you have a dedicated herb place nearby they could steer you in the right direction. I just have it in a window (and don't know about your lights, sorry).

If you want the common garden annual-type plants, only smaller, look for any of the varieties listed as "miniature" or "dwarf", either of which will stay below 15". A google search will give you some names. I've given one link, although they only mail to the UK.

There are also a whole host of more succulent Pelargoniums, summer-deciduous types, caudex plants, etc., if you want to get a bit adventurous. Some of these are also very small.

Here is a link that might be useful: Miniature Pelargonium list