I don't think there's any evidence for that as a significant factor. I took a look at the dollar exchange rate for a bunch of currencies over the last year and compared the high as a % of low.
In order of population:
Indian Rupee: 117% (high as % of low)
Euro: 106%
English Pound: 112%
Canadian Dollar: 110%
Danish Kroner: 105%
Swiss Franc: 106%
Icelandic Kroner: 110%
Right, but that's only a single metric - the key benefit of controlling one's own currency is that a central bank can try to steer inflation by the setting of interest rates. I have no idea, but perhaps the smaller of these countries have been forced to do this - which isn't all that great, unless it happens to coincide with what they'd want to do anyway (as a counter example, due to the recent sanctions, Russia is being forced to hike its interest rates in order to stem inflation, which is really the last thing it wants to do thanks to its sluggish economy, but the alternative of high inflation is worse). Similarly, smaller currencies - such as the Danish Kroner - have official guidelines attempting to bind them to other, larger neighbouring currencies, like the Euro. This is a good idea since they're obviously big trading partners with the EU at large, but it also offers a reduction in autonomy. Furthermore, these are all stable, established currencies, which a Scottish Bawbee could well become, but it's unlikely to be in the first place (Especially with some expectation of the shifting of industry from what's currently there).
In short, I think it's pretty inarguable that smaller currencies are more at the behest of larger currencies and the markets than large currencies are. The larger a currency, the less it needs to fight these stimuli to maintain stability.
