For The Love Of Port

...I can think of the following:

i) Noval (Noval LBV pic, Quinta do Noval single vineyard LBV pic - both unfiltered)

ii) Warre (Warre bottle matured/unfiltered LBV pic, Warre [filtered?] LBV pic)

iii) Dow (Dow "Master Blend" LBV [filtered?] pic, Dow unfiltered LBV pic)

iv) Smith Woodhouse (SW bottle matured/unfiltered LBV, SW [filtered?] LBV pics of both)

I am passing through here very quickly, so I'll have to give this more thought, but Fonseca comes to mind as another example. They do filtered and untiltered versions, depending on the vintage.