Joel Suss (FT( has an interesting, simple proposal for tax:
End most (all?) VAT exemptions, but (the important bit) provide real time rebates below a certain level (he suggests round 60% of median income - £20k) so the poor pay no VAT at all.
This would make the collection of VAT easier, but (the crucial bit) would need a workable system for immediate rebates (and then there would be the step-up problem when you passed the threshold wage).
But interesting idea nonetheless!