Waffen Greger, a German company, makes bullpup conversions of the Browning BAR (the hunting rifle, not the military BAR).

Once converted the overall length of the rifle is just 31.5″, about 12″ shorter than a standard BAR¹. Aside from the length, a significant benefit would be the better balance offered by the bullpup configuration, with the action sitting right up against the shooters shoulder.

The standard magazines that are supplied with the rifle hold just two rounds, although they can supply three or four round mags. In Germany, hunting with semi-automatic rifles holding more than two rounds is prohibited.

Many thanks to Mehul for sending me the link to this company.