A couple friends here have recommended the Airmotiv E1s... Not my style personally, but they said they perform well. On closeout for 168/pr. (FWIW) (Oh, and front ported too.)
Personally, I've been eyeing the Boston Acoustics A-26s from A4L to use in my Atmos rig. Still hoping to build my own AAs, but those look like a good buy. Rear ported, IIRC, is my only issue with them.
Are these going with your LS50s?