to my knowledge - which is Royal Artillery rather than a 'Scottish' regiment, the answer is fcuk all.
more than one person has opined that being the Edinburgh Gunner for life might be a passport to free sex with tourists, but none of the scots i know and who i've talked about it with are remotely interested.
they see two issues - firstly that they joined the Army for an adventurous life with lots of overseas travel, and the don't see there being any chance of that in an iScotland, and secondly they take the veiw that defence is going to take an absolute hammering in an iScotland - like down to Irish spending levels.
i have heard - so heresay - that its more popular (though not even close to 25% of their Scottish soldiers) in some of the RRS Infantry Bn's, though theres a number of splits: pretty much no Officers are interested, some S/NCO's are considering the merits of an easy life based near home, and the junior ranks are split between those who want to go on tour and those who fancy being posted to Edinburgh for the next 20 years.