I couldnt find any shops listing all the parts you'll need, but you could contact Robin Subaru
at this link:-->
http://robinamerica.com/contact.aspx
I'd sugest your email includes your engines model#, and ask how/where you could order
ALL the components you'd need for upgrading your engine to electric start with a high-output charging system, thats suitable for the lights you've selected. (be sure to include the # of lights you'll be installing, and info about your lights like: The candlepower or watt rating, or the amp-draw rating of your lights)
PS: Don't be too surprised if all the parts you'll need end up costing way more than purchasing a whole brand new engine thats factory equipped with these components...