I'll admit, I favour a federal solution, with more power devolved to the regions (probably following a German model, rather than the US), but I've never heard people object to it, as it's simply too obscure.
It does get a bit of notice here and there, and Gordon Brown has been pottering around tinkering with the concept for the last few years, but it's difficult because there are a bunch of different ways it could possibly be done and there doesn't really seem to be any will to seriously examine them.
At the very basic level, the establishment of an English Parliament with powers equal to that of the Scottish body resolves the West Lothian question because it leaves the current UK Parliament to only consider non-devolved matters. This would leave unchanged the fact that the vast majority of members of the UK Parliament would come from English constituencies, but there will emerge the question of the Lords.
Most federal systems are set up with measures that deliberately exaggerate the representation of smaller federal subjects in the upper house. Australia's Senate, as mentioned earlier, has 12 seats for each state and 2 for each self-governing internal territory. Canada's Senate is apportioned by region; 24 seats each for Ontario, Quebec, the Maritime provinces region, and the Western provinces region, then six for Newfoundland and Labrador together, and one each for Yukon, Nunavut, and the Northwest Territories. The German Bundesrat, meanwhile, applies a form of degressive proportionality where differences in population are only partially accounted for; a minimum of three seats for each state (including the city-states), but states with more than 2 million inhabitants receive four, more than six million inhabitants receive five, and more than seven million receive six.
The question then becomes, of course, how you would apportion such a system in the UK if you chose to reform the House of Lords along these lines. It seems probable that many people in Scotland - and also Wales and NI - would favour a system where receive more seats than strict proportionality would suggest, but I expect that the exact level of disproportionality would be a very fiercely contested topic when presented to the English electorate.
To me a system similar to Canada's could be a reasonable compromise - England would receive a significantly larger number of upper-house seats, but these would be apportioned to regions that are drawn up with regard to historic organisation and prevailing social and economic factors. This way England would remain a single polity, under a single English Parliament, but the regions can be better represented in federal matters and the composition of the upper house would be less likely to appear as one monolithic block for England towering over the other nations. You could even include a small number of seats for the Crown Dependencies and British Overseas Territories, if they wish to take them.
The first difficulty remains however that to actually adopt such a system you need to have all these discussions, and then decide on the option to go with, and then put it to referendum across the whole of the UK.
The second difficulty is the question of parliamentary sovereignty. A point of contention in the UK's present devolution arrangement is that the parliaments and governments of the devolved nations can be overridden by Westminster, at its whim and without recourse - while all of existing federal systems we've examined have written constitutions that clearly divide the legislative competencies of the federative states from the federal parliaments, and clear mechanisms by which the constitution can and cannot be amended. The UK Parliament has enacted such constitutions for a number of its former possessions, but imposing one upon itself would require an irrevocable renunciation of parliamentary sovereignty in order to guarantee to the states that that their competencies - or the federal structure itself - would not be infringed or altered by future acts of the federal parliament without their consent.
I said in my first post that I remain open to examining proposed solutions that improve with the UK's constitutional arrangements, and I stand by that statement - but I want to see meaningful and constructive changes, not just "we'll give you devo-max if you stop bothering us"
