It appears that a proper figure for
Shana-tan exists
Don't bother trying to search high and low for it though cause the company which made it , TJ Grosnet, had filed for bankruptcy back in April this year and all their possessions and assets have been seized by the banks. Originally it was only available to buy from their website but I think a few were sold at the Tokyo Toys Roadshow event according to the blog in the link. Consider this VERY RARE to get.
There's one up for auction over on Yahoo Japan Auctions right now but be prepared to pay 10,000+ yen for it.