Ask HN: Should I build my product or my portfolio?

I asked this in a thread about something else yesterday and could use some advice. It's about where I should focus my time to start bringing in some cash.

Should I focus on the product I want to build and possibly fail months later with nothing to show for the effort and no budget left to live on (I'm still recovering from the last one)?

Or should I build several smaller demo projects as portfolio pieces I can shop to get client work to fund the part-time development of my eventual product? Especially considering that my walled-off enterprise projects are inaccessible and built with tools other than the open source ones I'd prefer to be working with.

It's almost like starting from scratch.

For example, Rails ads usually specify "2 years experience with high-traffic production apps" or something like that. Should I build a bunch of small demos, free and consumer apps?

I'd be interested in reading any success stories here.