Re: $1500 probably means £1500
Lenovo makes one at the same price range, the Helix-B.
Dell could make one, their Venues are basically very fine systems by now and they have done tablet pc before (and well). What they currently lack is a good pen. Going back to WACOM like they did in the generation prior to the Venues would nicely solve that.
Samsung has the knowledge (They did a number of Win7 and Win8 tablet PC) and their prices (and sadly their build) are cheaper. Still, the final batches of the Ativ 500 series where sturdy and well behaved. An aquantance of mine still uses one without problems.
Asus could do it but strangely they never followed up their quite successful EP121 with a similar unit. Even their R7-572 "mobile grafik tablet" is no longer on the market. Nice and sturdy if huge and heavy unit loved by some painters/artists