Okay, I know that the latest polls showing the number of seats for pro-independence parties at over 65 are indeed just polls, but let's pretend for a moment that, come 6th May, the Scottish parliament does indeed have a majority of MSPs who support Scottish independence. The SNP wanted to get a referendum on independence in their first term in Government, but were thwarted by the three London parties ganging up to tell us that it was the wrong time for a referendum on independence (which implies that there is a right time - but they never told us when that was) or that in the "current economic climate" we couldn't afford a costly referendum (which is puzzling considering there is a costly referendum on a pointless change to the Westminster voting system on 5th May). However, if the polls are correct, then supporters of independence will have something to get very excited about: a referendum on independence will take place before 2016. But not only will we be getting a referendum on independence; we'll be getting it without having to worry about the vote being diluted by a "devolution max" option, and there is only one party to blame/thank for that: the Lib Dems.
In 2007, both the SNP and the Lib Dems wanted Holyrood's powers to be increased, to varying levels. The SNP wanted a referendum on full independence, whereas the Lib Dems wanted "devolution max". The SNP were willing to work with the Lib Dems by including a "devolution max" option in a referendum, alongside their independence option, but the Lib Dems were not willing to back down from their "NO INDEPENDENCE REFERENDUM!!!" stance. If the Lib Dems hadn't been so pig-headed, there could have been a referendum in the last parliament, and Scotland would almost definitely have voted for increased powers but not for full independence. I say this without a doubt in my mind, because the biggest fear people have when it comes to independence is fear of the unknown. So while most people would probably want changes made to the Scottish parliament's powers, many of them would be scared of going too far, so presenting them with an option of increasing powers but remaining part of the union would suit them much more than going straight for independence. I dare say there are many people who would one day support Scottish independence, but would need to see proof that it could work first, via increased tax varying and borrowing powers. This is why the gradualist approach is almost guaranteed to eventually lead to independence.
The Lib Dems shot themselves in the foot last time around. Assuming there is a pro-independence majority in Holyrood after the election, then we will see an independence referendum in the next parliament, and there is absolutely no requirement for that to have a "devolution max" option on it. Indeed, as I have already said, the appearance of such an option would guarantee defeat for the independence option, so it is to be avoided where possible. The Lib Dems could have made a difference last time round, but this time no one will even care what their position is. Without a "devolution max" option on the table, the Lib Dems will be left with no choice but to fall into line with the Tories and Labour in completely opposing the independence referendum, thus making it even less clear what the point of their existence actually is in Scotland. If the Lib Dems' main objective is preservation of the union (and, as I have mentioned previously, all the evidence points towards this being a fact), then they have possibly failed, as a referendum with a "devolution max" win would probably kick independence into the long grass for at least a couple of elections (providing ample opportunity for Labour to get back in power and run the country into the ground to convince people that Scotland really can't stand up for itself), whereas a straight "independence or status quo" referendum could deliver independence within five years.
Lib Dems will probably point towards the Scotland Bill the coalition is trying to impose on Scotland as proof of the Lib Dems taking action to increase Holyrood's powers, but the reality is these changes are going to be disastrous for Scotland, and their impending imposition may even help concentrate a few minds to consider just how exactly Scotland benefits from being ruled from Westminster. The bill could be the Poll Tax of this generation, and we all know what happened to the Tories because of that error of judgement. So, it doesn't matter if Tavish really doesn't now consider an independence referendum to be a deal-breaker or not, because it looks like his party won't be needed anyway. Which may hold true for pretty much every issue over the whole five year parliament...