I totally agree with this idea and i think its perfect.And a different vesrion could be that crossbowmen carry the huge shiled on their back and when they fire,they automatically stand still and turn around with their back to the enemy to reload and then they fire normally.Of course the shields on the back should protect totally and act like normal shileds and not say(shiled hit on back!).Took the idea from medeieval 2 total war.Its a little more complicated but its just a different vesrion.Its not that historically accurate but hey this is mount&blade nothing is historically accurate
Sorry for my bad English!
Here are some picures..(dont know how to insert them so i sent the adress)
http://www.google.gr/imgres?imgurl=http://img397.imageshack.us/img397/4729/pxbowug0.jpg&imgrefurl=http://www.twcenter.net/forums/showthread.php%3Ft%3D205348%26page%3D10&usg=__VeqL-VUjBbokty8b4uBWhYXHBXE=&h=596&w=723&sz=178&hl=el&start=0&sig2=ozdhCBwLTzSfL0NxqR1PeA&zoom=1&tbnid=XHEY0biM4Q8cIM:&tbnh=140&tbnw=170&ei=5LdiTevdBY-Wswa1gr25CA&prev=/images%3Fq%3Dpavise%2Bcrossbowmen%26hl%3Del%26sa%3DX%26gbv%3D2%26biw%3D1419%26bih%3D682%26tbs%3Disch:1&itbs=1&iact=hc&vpx=1146&vpy=400&dur=296&hovh=204&hovw=247&tx=120&ty=161&oei=5LdiTevdBY-Wswa1gr25CA&page=1&ndsp=31&ved=1t:429,r:30,s:0
http://www.google.gr/imgres?imgurl=http://totalwar.honga.net/images/medieval2/m2tw/unit_info/spain/pavise_crossbowmen_info.png&imgrefurl=http://totalwar.honga.net/unit.php%3Fv%3Dm2tw%26f%3Dspain%26d%3DPavise_Crossbowmen&usg=__LVriRdu9qJg9MDdmYO6PpQnD9_U=&h=280&w=191&sz=121&hl=el&start=31&sig2=Xss2bCl3hF2DCqwyKMOnsA&zoom=1&tbnid=IXZAgyzkZ1IrQM:&tbnh=172&tbnw=114&ei=8LdiTfXsKcWL4ga71cyXCg&prev=/images%3Fq%3Dpavise%2Bcrossbowmen%26hl%3Del%26sa%3DX%26gbv%3D2%26biw%3D1419%26bih%3D682%26tbs%3Disch:10%2C419&itbs=1&iact=hc&vpx=158&vpy=380&dur=188&hovh=224&hovw=152&tx=76&ty=182&oei=5LdiTevdBY-Wswa1gr25CA&page=2&ndsp=19&ved=1t:429,r:6,s:31&biw=1419&bih=682
http://www.google.gr/imgres?imgurl=http://i101.photobucket.com/albums/m67/Choibolsan/CHART/genoese20white20eagle20pavise20back.jpg&imgrefurl=http://planetfigure.com/forums/showthread.php%3Ft%3D22695&usg=__NDoqEAAOhwMKFZPjBQBRxQ3_kDg=&h=650&w=468&sz=46&hl=el&start=115&sig2=Z3IB_rTptCMTlel0T7MJrA&zoom=1&tbnid=UzYERGjiXrJgIM:&tbnh=161&tbnw=113&ei=DrhiTbyJHdCC4QbMsuWxCg&prev=/images%3Fq%3Dpavise%2Bcrossbowmen%26hl%3Del%26sa%3DX%26gbv%3D2%26biw%3D1419%26bih%3D682%26tbs%3Disch:1&itbs=1&iact=rc&dur=94&oei=5LdiTevdBY-Wswa1gr25CA&page=6&ndsp=21&ved=1t:429,r:20,s:115&tx=58&ty=46