It would be a real boon if you could buy soul bound furniture upgrades, so that you can use them on all pieces of the same type (eg allow Firebog style for all 100+ of my SDBs), but the upgrade would be restricted to items within your own home.
Obviously you would not be able to sell / trade / auction / etc items that are currently upgraded with a soul bound style, but resetting them back to a free or purchased style would probably allow sale.
This idea could possibly be extended to allow purchasing sets of upgrades (related styles across different furniture types).