Does anyone make a dynamo light buffer battery that will keep it going at full power? I have a nice SP dynamo hub and an old Supernova E3 Triple dyanamo light. However, the dynamo light isn't very bright when I'm starting my ride, as my ride has a long hill at the very start, so I don't go very fast. Then it's a lot of stop and go riding for the rest of my commute with a few more small hills. The standlight kind of sucks until I've been riding on a straight stretch for a while. Looking forward, I would consider buying new gear to help, but I'm not sure what I need (other than just only using battery powered lighting).

Basically, I want my bike to always have lights on while I'm riding through the winter months where I'm commuting both to and from work in the dark, and not loose lighting when I'm stopped or going slow on a climb (where I'm very venerable). Currently, I have to supplement having dynamo lighting with battery powered lights since the dynamo lights cut in and out due to my hilly commute with lots of stop and go urban riding.

Does anyone make an inline power buffer for dynamo based lights to provide (a) Immediate on when you want to start riding and (b) Constant power while stopped? Or are there lights or other equipment that provide this feature (without forcing me to build my own circuit boards and such)
There are standlights, which are essentially supercapacitors combined with LED headlights. They're designed to be charged from the dynamo while riding and give you a few minutes of extra lighting when stopped at a stoplight. However, all the ones I know will self-dissipate after a while, so they're useless for your purposes of starting off the day with full beam strength (unless you want to bike around on the flats for a few minutes charging them). 

For full strength lighting at any time, you really need a battery.

I don't know of any commercial battery-charged dynolights. I built my own circuit that takes the AC from the dynamo, rectifies it, uses the DC to charge an 18650 that then powers my LED headlights and taillights (and charges my cellphone). The circuitry is trivial by itself, but you'd have to know enough about soldering small circuitboards and I can't do any customer support, so I haven't shared it.  

The reason I built the rig was that I wanted more powerful LED night lighting (10+ watts) than my dynamo could reasonably deliver at one time. So I charge my 18650 by riding during the day; and then at night, I have instant full power.

My assumption is that if you know enough about electronics to solder it, you should know enough to design it. All parts are available from sparkfun in terms of rectification and smoothing, lithium batter charger, battery, switch, LED current limiter, breadboard, and so forth.