Hi Pannonsports,
As long as the overall options are the same for each product (e.g. all use size and colour - the same options) - then perhaps it can be done with standard options & variants...
If there is no logical link between ALL of the options, then I doubt it is possible given standard x-cart.
I am working from memory here and based on older X-Cart versions... so do excuse me if I am wrong
(but it seems worth a try given you are stuck at the moment).
I think you perhaps could set-up product variants for all these and then in X-Cart Admin "export" your "product variants" and set some of those product variants to be "not for sale" (this should turn off the ones you do not want shown - are unavailable). From memory I think this can be done...
e.g. Perhaps try to test one product, where you have two options (3 colours & say 10 sizes) e.g. Red (A to J), Blue (A to J) and Green (A to J) - then via export, turn some of those product variants to "not for sale" (to turn some of them off) and import your product variants back into X-Cart.
This means of course you will have a large list of variants where maybe only 1/2 or less are being used, but at least it might work...
This may work and be the only easy way...
Sorry I can't test this method now, as we don't use standard variants - but honestly if this doesn't work, you might be better to move to another cart (unless you are a very good programmer and can totally change how options and variants works within X-Cart).
Cheers - Asiaplay
PS: I am assuming that V4.3.X does allow you to set some product variants to "Not for Sale" (via CSV, when it doesn't on the Admin screen) with the above suggestion - but never used this version before...