Check with Brownells. They have a great selection of bolt handles that can replace the handle on the Mauser.
I don't know if you ever intend to scope the rifle but if you do you will want to change the safety to one that will be easier to use with a scope. Both Timney and Bold carry selections for the Mausers with and without integral safeties. You can mount the scope lower wihout interference from the safety. You will also need a housing to replace the one the safety mounts to - couple of $...... Overall expense...cost of the new bolt handle, $25-50 to have it put on and polished, replacement safety cover (or what the heck ever it is called) couple of $. No hassle for a good gunsmith.
Suggestion: the Mauser bolt operates on a 90 degree arc. Many gunsmiths cut and weld to about a 45 degree angle, which means that when you uncock the action and bring the bolt all the way up you have very little room for fingers or gloved hands if the rifle is scoped; it's a tight fit. A flat bolt handle or spoon handle reminescent of the Mannlicher Schoenauer would give you a bit more room, or the ability to 'slap' the bolt handle from the bottom and operate the bolt with the palm of your hand if the need be. With this in mind you may wish to talk to the gunsmith about welding the bolt handle closer to a 20-25 degree angle to give you more room between the bolt handle and the scope.
I don't think you are going to find a stock that is custom you your 19" bbl without ordering a custom stock or a custom cut stock. It may not be much more $ than a normal size stock but ya ain't got a normal length barrel. The M98 usually came with a 23 or 29" bbl; some of the 93 or 95 7mm Mausers came in a shorter carbine length but they aren't 98s. Unless you can order one to your specifications you will need a gunsmith with stockworking skills to contour the stock to your aesthetic preferences so that it gives you both the look and feel you want. It may not cost a lot. HTH. Mikey.
