Hi Gio All of the ones that Lavendar suggested are good.
My personal experience with Greenhouse seeds is good. My favorites are Lemon Skunk and Adrian's Strawberry Haze. The haze would be too tall for you though. Lemon Skunk seems to stop at around 4 feet and really packs on the buds. It has a great high too!
What ever you do....do not order their group of colored seeds on a card! They suck! Hardly any ever pop! Have (my last of those devils) 3 germing now
and after three days in the usual paper towel on plate with saran wrap and nothing! Don't buy any!
Barney's Farm has a good indica called Violator Kush. It is powerful smoke and stops at 4'. If you top her she will have many buds and will stay low.
I use Single Seed Company all the time and now they include a couple of good seeds for free. I've never had any problems with them.
Attitude is a good company too, just ordered from them this week. Once again never had a problem with them. Attitude also sells single seeds. Look under Pick and Mix seeds. Especially read they're news letter and their UFOs.
At times you can do what I have done multiple times.....spend 30 bucks for a couple of seeds and get a total 7 or 8 seeds.
Hope this answered your question or at least gave you something to look for.
Thanks OMM, I really appreciate the heads up. I am looking at single seed right now and doing some research on all of the strains that I am interested in. Also looking into possibly re-purposing the shed that I was using for flowering. Im thinking that I might want to try crossing some things down the road =).