Steve... At some point or another in making a songwriter demo, you ARE going to have to record your voice (and anything else you need outside the arranger).

The Roland arrangers have no recording (audio) capability. The sequencer is quite powerful, but more linear oriented than you indicate. However, with an arranger, getting your verses, choruses and in/out sections in one pass is a snap. Once the building blocks are down, it's easy to cut them up into the component sections, and rearrange those if you want.

But, at some point or another, you are going to have to transfer it to a computer DAW, and do the acoustic stuff. BTW, THIS is where you'll be applying any pitch correction you need. Donny is mistaken in thinking this won't be needed... Every pro recording done nowadays uses Auto-Tune or equivalents - at least subtly.

If using a DAW is completely out (I wouldn't recommend this, but it CAN be done), your choices narrow considerably at the price point you can afford. Only WS's (and even those are on the high dollar side, like MotifXS and FantomG) have usable multi-track (that part's important) audio recorders built in. Arranger audio recording tends to be more 'one take scratchpad' features.

But an inexpensive computer (you are probably posting on it!) can do quite sophisticated audio production at a bargain price. All of my production and songwriting demo work is done this way... Use the arranger to get the rhythm section fine tuned, then record to the computer, add the vocals, acoustic instruments (and maybe some cutting edge loop stuff if you need it), mix and master in the box. Simple, powerful, inexpensive.

The final choice as to which arranger, I feel, should be left to your ears alone. Advice from here rarely comes from those with the same goals, age group, music tastes and skill level as you. Auditioning them for yourself, getting to know the differences in 'sound' and style choices (style CREATION is fairly complex) that the arrangers have is paramount. I would NOT recommend buying sight unseen.

But your short list to audition, I think, at your price point should probably be Yamaha S900, Roland E60, and Korg PA500 (should be over here soon). If you are writing hiphop, techno, rap, etc., you might also take a look at the Yamaha MM6. Very inexpensive, but can do those style better than most arrangers.

If you MUST do everything in the keyboard (not my recommendation!), you might save a bit more and spring for a MotifXS, or maybe (when they get here) a new FantomG-series. but you'll need an extra $500-1000 over budget.

Hope this helps.