I'm not really sure why I would want to add a second monitor to the 27" Planar monitor I already use, but...  Bigger is most often better, or so it seems to me.  I just called a  sales rep for the ZOTAC ZT-MDP2HD Mini-DisplayPort to Dual HDMI Adapter (at superbiiz.com) referenced above for $42.99.  This splits the MiniDisplay Port out of the Surface Pro into two HDMI ports.  The sales rep said if it doesn't work for the two monitors, I could get my money back.  They don't, of course, offer technical support, but he did say they have about 5 in stock.  I'm going to order one just to see if I can hook up my other 24" monitor to my poor little Surface Pro.  Why not?  For less than $50 shipping included? Also, since this is, apparently, only a minidisplay port splitter, it doesn't have to burden my single usb 3.0 port, which is already used by about 7 other powered and unpowered items on my desk.
I don't need touch based monitors since I don't like gorilla arms as Steve Jobs said.  But, I could find an use for up to two 27" monitors, even though I am not a heavy duty stock trader or a mission controller for earth to space rockets.  But, I like to play one on TV.