Those RX100 shifters sound like a good deal. You can run them with an 8-speed cassette if you want, because they'll friction shift past the last indexing point. I have those on my road bike.
As for other options, you'll soon find that brifters are crazy expensive. What I've been planning on doing is getting some bar-end shifters (with however many speeds you want.) To me, they seem like the best balance of cheap/reliable/and ability to shift from the bars.