Probably not what you had in mind, but I crossed over into MERP from D&D. I ran a three year campaign set in the last few years of the First Age/first few years of the Second Age. When I discovered MERP (and later Rolemaster) I translated some of the D&D magic items over into the Rolemaster system. Most are too low-level for what you had in mind, but among the useful ones (from old Dungeoneer's Guild adventures) were:
The Wand of Elbalond — found in a dragon horde, it combines the powers of the Staff of Power and the Staff of Wizardry. Basically, find spell lists from Rolemaster or MERP that match the D&D spells, then allow the wand to cast spells of up to 20th level from those lists. I gave the Wand (which at command can become 2', 4' or 8' in length) 400 power points per day, half of which could be used to cast spells and half to manipulate them (increase range, duration, etc.).
Less powerful were the Wizard's Belt and the Prayer Beads. The Belt allowed the wearer to cast spells from the realm of essence as if the wearer was 3 levels higher (also increasing their power points, spell resistance, ability to overcome spell resistance, etc.). The Beads allowed the user to treat every spell cast from the realm of channeling as if they'd rolled a natural '00'.
Similar were the Belts of Giant's Strength, which granted the wearer a strength of 101-107, depending on which belt they found. In your campaign that would probably be 106-112. A Belt of Giant Strength combined with a Hammer of Thunderbolts (or a Dwarven Throwing Hammer in the hands of a Dwarf) can be pretty impressive.
And there were others; a Ranger Blade, a suit of chainmail (AC-16) for the scout (treat as AC-1 in Rolemaster/no armor in MERP), and many items of lesser power.