Anyone know of a hair product that gives a matte finish, has a really strong hold for heavy hair and is gentle on sensitive scalps? And if possible, is more like a cream than a wax?

American Crew Fiber. This is what you want.

There's a really good Japanese product called "Gatsby Moving Rubber." Look it up. You can find it on eBay for around $10 shipped from Asia. It's available in several different strengths, depending on how you style your hair. Incredible hold, yet completely soft and can even be restyled through out the day. I used to use Fiber, but it didn't do much.

I have really thick course black hair, fiber never really did it for me. it usually just left my hair in clumps. What has really worked has been the new American Crew Forming Cream. I just apply a little bit and it does its job without looking overdone or shiny

I like Lush - Jungle , it's actually a bar conditioner, so it's healthy for your hair and scalp, but has a good hold. I take a small (TINY) piece and rub it into my palm to make it a sort of pomade. Holds well and lasts, is matte and keeps my hair feeling decent. If you don't have a Lush nearby, you can order it from their webstore.

I swear by Baxter of California Clay Pomade. It provides fantastic hold all day, delivers a dry matte finish and while the word "clay" sounds like it would simply be heavy and messy, it's incredibly fluid and doesn't clog pores or follicles.

Try Precision Putty from Gillette for a great hold with a matte finish. For easy distribution warm putty between your palms until a thin layer is spread evenly over your hands and then work through your hair.
http://www.gillette.com/en-us/#/products/haircare/en-US/index.shtml/

Sumotech is great but just do not expect a super hold like a gel though.

...a little trick I learned, if you heat it up with a blow dryer, it will become much more pliable.

You can also mix products (sumotech with a bit of gel) to get more hold.

On the cheap end, Axe Whatever Messy Look paste
I have fine, medium blond hair, and can't stand anything that darkens the color. Have tried everything in pastes, pomades, gels, glues, etc, from d:Fi, American Crew, ICE, ShortSexyHair, and many more. All of them would wear out very easily and make my hair dark, shiny, hard, or gooey. The Axe product holds for a long time, doesn't change the color of the hair, and doesn't feel heavy. It's worth a try for less than $6.

I use American Crew Forming Cream. I have very thick hair and it holds my hair very well throughout the day. Also I was never a big fan of the "wet hair" and this product is perfect for that. Not shinny at all.

This is an easy one for me. I'll put in a good word for Paul Mitchell's Tea Tree Shaping Cream. I couldn't stand waxes and gels, and having my hair look like it was constantly wet. The Tea Tree Shaping Cream is strong enough to keep my hair in place all day, while still looking natural.

Try Osis+ marsh mellow molding paste. Its stronger than Sumo tech and wont get oily at the end end of the day like other pastes. Make sure your hair is dry when you use it. This is key.
Heres the link -> "osis Marsh mellow molding paste"http://products.ask-schwarzkopf.net/index.php?cid=107&l=6&pid=10357&prev=894&f_id=894&lid=894

Aveda Pureformance grooming clay. A little on the expensive side but a container will last months. I've used the American Crew and Garnier, but the Aveda is far superior.

The absolute best product in this category is Aveda Men's Pure Per-formance Grooming Clay: http://www.aveda.com/templates/products/sp.tmpl?CATEGORY_ID=CATEGORY14928&PRODUCT_ID=PROD11868
I received an unbelieavble amount of compliments on my hair after I started to use this product, and it's my best kept secret. Put about a nickel sized amount on the palm of your hand, rub it between both of your hands, and just run them through your hair.

The absolute best product in this category is "Aveda Men's Pure Per-formance Grooming Clay": http://www.aveda.com/templates/products/sp.tmpl?CATEGORY_ID=CATEGORY14928&PRODUCT_ID=PROD11868
I received an unbelieavble amount of compliments on my hair after I started to use this product, and it's my best kept secret. Put about a nickel sized amount on the palm of your hand, rub it between both of your hands, and just run them through your hair.

Fudge Hair Shaper.