Digital BW, The Print

Greetings!

I have another matting/presentation question and Thank-You-So-Much 
for continuing to help me make the transition to inkjet/digital.

With my darkroom setup, I usually printed 11x14 matted to 16x20 and 
was happy with this style and have a slew of standard frames and 
boards that lets all my work look consistent and allows me to swap 
in and out of frames for display in my home gallery space.

Now I am beginning to shoot a bit (and probably a whole lot more) 
with a DSLR with a much wider format than my 6x7 or 4x5 cameras. So 
now a typical print with my R2400 is coming out in the 11x16.5 range 
and clearly 16x20 boards are not going to make it any more. Clearly 
too I can go a little larger with the 13" printer. Cropping back to 
an 11x14 aspect ratio is not always possible or desireable if I have 
used the full camera format in my composition.

So what have advice would you give me for a standard mat size to 
display prints like this? I would like to standardize on an 
attractive size mat/frame to aesthetically diplay this type of 
aspect ratio. Are there any standard thoughts here or strong 
preferences?

Thanks again for your continuing encouragement and help!

Scott