2nd-init should work. CVPCS did a blog post the other day saying it is possible on Gingerbread kernels. This is good news for the Bionic because supposedly the exploit used to root the D3 exists in all the Motorola phones, so hopefully we'll have root at launch or soon after.
ALL Motorola phones? Heck yes! Yeah so we SHOULD see it work on the Bionic, they already should have finalized everything by now, so unless they update it as soon as I turn it on, there won't be anything stopping us.