Sony just announced an external Blu-ray writer that is compatible with 100 GB BD XL discs.
According to Sony, the BDX-S600U can read and write CDs, DVDs, DVD-RAM, Blu-ray (25 GB, 50 GB) and BD XL (BD-R XL) media. The write speed is 8x for DVDs, 6x for single- and dual-layer BD-R and 4x for BD-R XL discs. the data read speed is 24x for CDs, 8x for DVDs and 6x for Blu-ray media.
Street prices for the BDX-S600U range from about $160 to $220.