Hi Skippern,
As Wolfhound mentioned, Fantasy Grounds with a full or ultimate license and the Rolemaster Classic ruleset will handle most of what you are looking for.
Here is how Fantasy Grounds will handle some of the items on your wishlist:
#1. It won't handle map creation but will allow you to add any jpg or png images to your campaigns so you will need something else to create your maps. It will handle most of the other stuff though.
You can create story entries with details of your campaign or adventures. These can contain links to other story entries, images/maps, NPCs, etc.
NPCs can be created from scratch or you can use something from one of the included library modules as a starting point. You can drag an NPC from the Character Law Non-Player Character Table (10-18) or from Creatures and Treasures into your campaign.
#2. Fantasy Grounds is a windows native application. I haven't tried it with Mac or Linux but I know that there are users that play using Mac and Linux. For Mac, you can use something like WineBottler or something compatible. I don't remember off the top of my head what they use for Linux. There is more information including guides here:
http://www.fantasygrounds.com/forums/forumdisplay.php?41-The-House-of-Healing.
#3. There are 3d dice that you can double click or drag to roll. There is an option for any roll that resolves against a table to use the stack. This allows the GM to resolve the rolls by right clicking them in the stack. This will look up the results in the appropriate table and let the GM manually adjust the results on the table just by clicking the cell you want to use instead. The GM can then right click the cell and choose resolve to open the critical or fumble table associated with the result. The result of another roll can be dragged onto the critical or fumble table to have it look up the results.
You can also have your players roll most of their rolls in the dice tower so only the GM sees the results or the GM rolls can be hidden which allows the GM to just show the results if they prefer.
#4. Character sheets, notes, handouts and maps are handled in Fantasy Grounds plus a couple other things.
It isn't a full character creator but it does have automation to help with stat generation, stat generation and skill development. Notes can be create by the GM or the PCs.
Handouts can be either text based using story entries or using images. You just set them up and share them with the PCs when it is appropriate. Images can even have a mask to hide portions of them until the GM wants to reveal them.
As stated earliers, Fantasy Grounds isn't a map creation tool but if you have maps they can be added as jpg or png images. You can then share them with the PCs, use a mask to hide portions, add a grid, add tokens and draw points, circles or squares on them.
The combat tracker will keep help track of the PCs and NPCs including hits, PP, effects, notes, exhaustion, and a move % calculator.
The GM can access the attack, critical, fumble, MM, RR, etc. tables from Character Law, Arms Law, Spell Law and Creatures & Treasures.
There is a calendar that includes 2 notes sections for each day. One that the PCs can read and the other that is only usable by the GM. There are about a half dozen different calendars to choose from include the Shadow World calendar. You can even create your own calendar if you don't mind modifying XML. If you aren't comfortable with that just let me know and I can help with it.
Please let me know if you have any questions.
