I know of 3 kits
GR Research A/V-3
Parts $340 per pair
Front baffles with precut holes $70 per pair
Cabinet plans
The M130 woofers are very good for their low price. They are the 16 ohm version of the same woofer Dennis Murphy uses in his excellent
MBOW1 design. I don't know anything about the tweeters.
Zalytron's Zeus - A transmission line kit comprised of the Hiquphon OWII and a pair of Seas Excel W18EX001 drivers in an MTM configuration. We had many customers suggest this combination. Crossover Call for enclosure design.
Parts $800 each
Cabinets $500 each
Look on the left banner on Zaltron's home page. Scroll down to Kits, click on Hiquphon. The Seas Excel W18 woofers are the same as in the Salk HT1, HT2, and HT3 (as a midrange) as well as the Thor kit below. The tweeters are the same as in the standard SongTower. Although I haven't heard it, this kit has excellent components.
Thor kit from Madisound
Parts only $1365 per pair
Madisound has various options with cabinets available
Cabinet plans
This kit, although expensive, has an excellent reputation. It uses the Seas W18 woofers mentioned above, and a Seas Excel 1" dome tweeter.