Good question! Dotmobi is very hard to characterize in such a way because certain names go/will go for very high amounts because of their relevance to the mobile market.
For general words, I'd peg dotmobi somewhere between .info and .net although this is by no way an accurate measure granted the above.
Something like sex.mobi could conceivably be a very high XXX,XXX -- maybe even 1m to the right person... Hard to say at the present, however I would imagine it has considerably more marketability than the .info and likely the .net
Other names -- such as general terms like "computer software" may do better in other extensions due to the fact that people likely aren't interested in looking for Office and Photoshop deals when they're on their cell phone.
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As for markets to look for names in... My best advice would be that Overture is your best friend! I got many good names as late as early March doing such and I'm sure there still are some. Type in any general word that comes to mind and look at what combinations Overture returns.
By typing in some words like cards, for example, I was able to get compactflashcards.mobi -- a type of memory card for cameras, certain cell phones, laptops and pda's. It's alot easier at this point to search this way than trying to think them up on your own.
Best of luck and congratulations on regging your first dotmobi. May there be many more
