My favorite Brookie rod, and quite honestly my favorite rod I own is a 6'11 4wt LLBean Streamlight Ultra. Only downside is it's a 2 piece. It's a classic middle of the road med/fast. It's low $100's in price. Not sure they make it in that size anymore, but I know there's a 7'6 4wt in the current lineup.
I also have a 7'6 3wt Redington CT 4 piece that I take on my backpacking trips and when I travel. Med-med/fast-ish and about $150. It's a good rod, and I fish with it as much or more than the Bean due to its packability, but I like the Bean better.
Understand that the St. Croix Imperial is a VERY, VERY fast rod, at the extreme far end of the spectrum on the fast side. One of the fastest I've ever casted. It didn't suit me, but a lot of guys like it. pcray, who I consider one of the best Brookie anglers on the site, I believe uses an Imperial as his Brookie rod. I'm sure it has the punch to make to make tight casts on small streams, just make sure it suits your casting preferences. Depending on your stroke and preferences, you may find a more med/fast or medium action rod has more punch in your hand.
Regardless, a 7'0 - 7'6, 3 or 4 weight is the best overall compromise on length/weight specs for a Brookie rod IMO.