video by KEYBOARDS NOSTALGY
This appears to be the first one pictured on the site. There are a couple of references to the HALO ROM sounds but not the actually keyboard synth. Some pics and details of one I found on eBay:
via this auction
SN 030200610

Halo also gives you 12 real-time controllers that put Halo's powerful synthesis features at your fingertips. You can tweak Halo's filters, LFO's, effects and more – giving you total performance control over your sounds. And Halo's 16 syncable/programmable arpeggiators and interactive Super BEATs Mode are perfectly syncronized with each other and over 100 rhythm-based synthesis and effects parameters, letting you perform entire pieces in real-time, all in perfect unison. Together with pristine 24-bit analog outputs and a lightning-fast processor, Halo offers professional results and playability at an incredible price.
61 keys
64 voice polyphony
32 MB Soundset w/ 640 factory/512 user presets (expandable to 128 MB)
16 programmable real-time control parameters/preset
16 simultaneous/syncable ARPs
SuperBEATs interactive Groove Mode (w/16 trigger buttons)
24-bit dual stereo effects processor
Four 24-bit analog outputs"