The new (and only these are available now) Maglite Xenon bulbs for C and D-cell lights ARE indeed bi-pin bulbs. In every pack, you get an adapter to make then suitable for the PR-socket of your Mag...
Brinkmann made bulbs for a while.
Bipin? I don't think they ever did those for C/D lights but their krypton PR base were on par with Maglite and are still readily found at eBay. The best PR xenon were Maglite but they are getting pretty scarce.