Hi, Halbrust!
I would recommend that you start by checking out the timeline here:
http://www.metmuseum.org/toah/ht/?period=07®ion=wai
Search for images of art from the various dynasties around your time period (Seljuk, Buyid, Ghaznavid, maybe broadening the geographical range to Abbasid). This will give you a good idea of the general profile. You might also try asking on the sca-persian yahoo! group, though many of the people there have late-period (Safavid) personas.
I did a bit of hunting myself. In general, the images I found showed pointy toed shoes or boots with no obvious closures; it's possible that the images just didn't have a bunch of details, though. Maybe somebody around here can suggest a source for pointy-toed, slip-on shoes or boots?
Some specific links:
c. 1300 plate with a Seljuq horseman wearing long pointy-toed riding boots (in turquoise glaze):
http://www.metmuseum.org/toah/hd/iselj/ho_51.53.htm
Another Seljuq plate with more riders:
http://www.metmuseum.org/toah/ho/07/wai/ho_57.36.4.htm
1330s manuscript (illustrates Mongols, shows lots of feet):
http://www.metmuseum.org/toah/ho/07/wai/ho_33.70.htm
Australian re-enactor's page on Seljuq clothing (sadly lacking in footnotes, alas, but if you want an outline to verify or argue with it's a place to start):
http://www.levantia.com.au/clothing/turk_man.html
--Ursula Georges.