Looking good mate. Not to discredit your work in any way, but the T34 tractor/APV's I've seen have two hatches (cupola and another) on the welded steel plate over the turret circle.
*finds a pic*
[link=http://img528.imageshack.us/my.php?image=t34apvmu6.jpg]

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WSN T34 is 2nd/3rd on my "gotta have it" list... Hows the ESC and mixer going?