This is a great idea. Just a fun mod. In theory you can make the kit graphics transparent, but i assume that the layer underneath a the kit is nothing nice to view. However, if teams in teams had the same skin colour (it'd have to be like a all-star black skin and white skin format) then you could make a jersey that looks like the chest and biceps.
The shorts would be the same and the socks could be set to down.. but then they are still playing with boots.
You'd have to again make some boots that match the skin tone that look like feet, and also the socks to look the same as the skin tone.
It is possible. It would be odd to see Twickenham like a sand pit lol
The best thing, at least the animations would look real, because you can't really sprint too fast in the sand.. and sometimes when you get the dust that comes off the scrum.
****, this game now seems more in tune to beach rugby when i think of it haha
If this could be a real mod, it'd be best to have some extra stadiums added (like for MUP) in some country like Mexico, and just port over the training pitch and a couple of other small pitches that aren't used much and add the sand/grass texture for them, possibly south africa as the texture is almost sand anyway... lol
Then assign a configured boot/foot for the skintone. You'd have to have a new roster, or else they'd play in boots.