I noticed some very old threads about the MetaWatch and one recent one on the Pebble smartwatch. For those who aren't aware, the MetaWatch seems to be way more open to custom Bluetooth development (a good example so far is the Sowatch app which communicates with the MetaWatch from the Nokia N9/N950, which run on the MeeGo OS).
I don't know how difficult might it be to port the existing Community Edition manager app that runs on Android or Sowatch over to webOS, but I'd be willing to help in whatever way(s) I can, however I have no coding experience personally. From what I understand, Bluetooth SPP needs to be present on the device you're pairing the watch to for it to communicate (check documents on their site for the exact details). I own an HP Veer 4G & could see buying a Pre 3 if the Metawatch can somehow work with webOS as I love the flow & usability of webOS & like the portrait slider design of these devices. I also like Synergy, which is a concept that seems to have appeared first on webOS & is getting similar communication integration methods in other OS but it started with webOS.