Regarding legroom and interior spaciousness:
The Beck speedster built by Carey and Kevin Hines, great people, has the most space in the leg area. It's a beautiful car from a stand up company. My issues with a Beck are few. I prefer IRS and every Beck I know of is swing axle which is like the original speedster but it lacks the handling of an IRS car.
Regarding legroom and seat position, I believe all builders can accommodate the "Big and Tall" by dropping the seat platform. Just ask @Stan Galat or @Tom Murtaugh.
If solid, roll-up windows are important to you, then Intermeccanica is the only company offering them.
Raj, I don't know you or your driving style. I know you're looking for something for casual jaunts and the occasional three day mini vacay, but in an ill-fitting car, even an hour is torture. Stan wouldn't be able to drive my car more than a few miles because his head is way over the windshield and his arms are doubled back on route to the steering wheel. I can't drive Stan's beautiful IM because I would need a booster seat to see over the dash and wood blocks fasten to the pedals to reach them. We are within a couple inches of the same height.
Talk to Henry, talk to Carey. And, by all means, talk to Greg Leach. He is a stand up guy who is taking the more modest Vintage Speedster to new heights. One of these guys will build you what you want. But a caveat here: there will always be follow-up modifications regardless of what you spend up front.