My company is headquartered in and old building that has been converted into an office building. It is a turn of the century building, four stories with the attic included as the fourth floor. It has the original sawn cedar shingles nailed to a solid plank wood deck, and has never been re-roofed.
The style is a combination of hip and gable, with several dormers at all sides, and long lengths of metal ridge and valley flashing. A near century of patching and repair no longer prevents the roof from periodical leakage, and it needs to be replaced. The building is listed as an historical site, and replacement roofing must be shingles, although not necessarily wood shingles.
A local roofer has recommended asphalt composition shingles. Since the cedar shingles have been intact for over 80 years, it would be logical to replace the roofing with cedar shingles, but our budget would not permit it. How does this sound to you?
Your roofer's ideas are O.K. I would tend to pick a 25+ year composition roof, and you might want to look at various different styles and patterns. I think that you will find a good match to the style of the building.
A key to maintaining the 'original' look of the building may be in restoring some of the decorative flashing and trim. You may have to hire a carpenter to work with your roofer in order to restore these decorative elements.
There are many other types of 'alternative' shingles, but these choices are going to be more expensive.
Even if you had the funds for a cedar roof I would not suggest that you go with cedar. The new cedar material is of lower quality, mixed grain and flat grain material. New cedar shingles will never last as long as the original material.