Kodak ImageLink microfilm is sold in non-perforated 35mm. It is rather difficult to get but is still avaliable. But...most vendors require that it be bought in multiples of many 100ft rolls (about $20 per roll). Speed for continuous tone (with very restricted latitude) is only about EI 2. For development try giving HALF the development time as for Pan F.
I used to deal with this person at inceptiontech.com: firstname.lastname@example.org. The location is 1 Sundial Ave, Suite 214, Manchester, NH. The phone is 603.222.2202 ext 212, or toll free: 877.475.2580. They sell it rebranded as Kodak Professional Film. I think that they required minimum of 50 rolls though. But you can get techical information and possibly others might wish to divide - David Lyga