This bug is separated out from bug #651606 comment #9 (2010-10-08) and recently highlighted by Mark Shuttleworth.
An Ubuntu Circle of Friends is present at U+E0FF ('') in the minuscule form used as part of the Ubuntu Font Family logo type. This is too small for practical use. This glyph should be kept (see below), but changed in the mapping to a full-width variant that is approximately cap-height, and em-width. The CoF roundel should match the dimensions of the roundel used in the CANONICAL bullet logo when set at that. This is the overshoot heights of the capital 'O', and circular.
1. Keep the existing glyph, but unmap from that the code-point U+E0FF
2. Create a composite glyph either way around), scaling the logo, such that it is cap-height and of the same dimensions as the Canonical Roundel
3. Create a two composite glyph feature featuring "u,b,u,n,t,u,existing small glyph"
3. Add a ligature/ccmp mapping "u,b,u,n,t,u,uniE0FF" → composite glyph of exact Ubuntu work mark, formed purely of existing glyphs
As this is only twiddling the existing proportional glyph mappings, I don't (think) it should require hinting changes unless there's manual deltas in use.
Ubuntu Mono:
For U+E0FF in Ubuntu Mono (without the flexibility of a variable advance). I have no idea whether the ligature replacement would work (it would need creating as new glyph form), so we may have to leave it as-is for Ubuntu Mono. It would be have to be shrunken down to 500 f-units, centred around the mean centre of gravity (vertical centre of '0', 'O') if it was added, but that might be fairly close the current anyway.
PDF (hopefully) demonstrating request, in two steps:
1. First, unmap the existing tiny logo from U+E0FF, and remap it with a scaled version;
then
2. Lastly, create a ligature/ccmp (hopefully more robust than "!ubu". The former was removed by LP: #651606.