Ghillie suits actually should take up half of your daysack. They're bulky items. Same goes for a full set of uniform once you switch out. Unless you're carrying a sizeable pack, you're not going to have much space for anything other than a couple of spare mags, your blowout kit, some food, water and other essentials. And that's how it should be.
If you ditch the AT weapons you might find enough space for both your long rifle AND your ghillie suit ;).
Seriously though, I think the current vanilla set up with the Ghillies is near enough spot on, even for a ghillie shroud.
