I thought a pepper beer would be a great idea. I used a blonde ale kit from my LHBS and added a habanero tincture made with 100 proof vodka. I tired a few different tinctures. One with jalapeno sliced with seeds, one with jalapeno without seeds, one with sliced habanero with seeds. I didn't care for the pepper flavor from the jalapeno with and without seeds it was too green peppery and didn't have the heat to balance it out. The habanero had the best pepper flavor in my opinion but had a crazy amount of heat. That is why I tried the habanero tincture in the secondary (the pepper and vodka). Turned out crazy hot, not too much that I couldn't drink it but hot enough to not really want another one if you could finish it. I don't think I would revisit a pepper beer but it was a fun experiment.
My suggestion would be to split up the base beer. I split the beer at secondary into a 3 gallon carboy and a couple 1 gallon jugs to experiment with. That way if it turns out bad you don't have to choke them down or dump the whole batch.