New 06 cranks are reasonably priced- around the $1000 mark when I priced one a while ago. Not sure if they carry stocks though....
Other alternative is contact Ben Ballard ?? (jbsracing.co.uk) who builds HD stroker cranks to turn them into 750s, either use one of his brand new counterbalancerless cranks or he may have a 650 crank lying around after doing one of his 750 conversions