It looks like Zune HD users will soon have another option to consider when looking for an external speaker system. Kicker has just recently made the ZK350 and the ZK150 available for pre-order.
In terms of pricing and availability, both models can be ordered as of now. The ZK350 will set you back $199.99 and is showing a yet to be announced (TBD) shipping date. On the other hand, the ZK150 is selling for $179.99 and is showing a shipping date of "on or before 12/1."
Feature wise, the ZK350 (pictured above) offers a 4.5-inch square subwoofer as well as two 4-inch woofers and two 1/2-inch tweeters. Additionally, the ZK350 offers composite video out, audio out, an aux-input for other MP3 players, 3.5mm headphone jack and ships with a remote control. This model also has an optional accessory (a battery back) that can be used to make it a truly portable system. Otherwise, it uses a standard power outlet for power.
The ZK150 (pictured above) is a little different feature wise and is touting a digital alarm clock -- or more specifically a dual alarm. It also as an internal battery backup, just in case you lose power during the night. Other features include a 5 to 120 minute sleep timer, 3.5mm headphone jack and aux-input for use with other MP3 players. Finally the ZK150 is available in either black or white.
Additionally, both units are compatible with all Zune models.
As for quality, Kicker is wonderful. I reviewed the iK500 (for iPod) speaker system a while back and fell in love with Kicker. That said, the ZK350 and ZK150 do not seem as powerful as the ZK500 (the Zune version of the iK500), but they should still be worthy of consideration.