Have an issue and looking at skirting boards which are 18mm thick (wife wants the tall 138mm ones which come thicker unless get them custom made which is more than double the price) but architrave is 11mm. Not overly keen on replacing all the architraves. Has anyone ever bevelled the edges of the skirting board? Any examples of what it looks like? Thanks.
I did this with my Philadelphia home. Below is the best picture I could find. It's near impossible to tell from the picture (and this is not the most flattering angle), but the baseboard is thicker than the side case molding. I simply beveled it to even with the casing at about a 45 degree angle with a block plane. I did not use shoe molding; instead opting to scribe the baseboard to the floor. The bevel actually helped the install look more detailed and "craftsman-like", in my opinion.
By the way, just in case it needs to be said: You will need to use real solid wood to do this.
If the architraves is the trim around the door, a plinth blocks are an easy, traditional way to remedy the differences in thickness. It will require the removal of the bottom portion of existing trim to install.