Audi R18 LMP uses Xtrac Sequential, there are lots of ratios available for each gear and usually several final drive, similar to hewland / ricardo offerings. The limitation is more on the real life race regulations which often limits the ratios used. I have read the 2014 ACO LMP regulations, no limit of ratio range specified, but the number of forward gears must be less or equal to 7.
For 2014, Xtrac specific LMP1 transmission with 13:46 to 19:39 straight cut gear ground final drive ratio are available as standard offering. A lot of range for adjustment for the final alone. While for 1st and 2nd layshaft gears are integral, and 3rd to 7th are slide on with a wide range of available ratios. The 3rd to 7th can be from 13:26 to 25:24 based on Xtrac typical gear ratios.
For the BMW 1M, in real life one can fit hewland or xtrac sequential box or other aftermarket offerings, lots of ratios to choose from, money is the limit.