Images courtesy of Heritage Numismatic Auctions

Significant examples:
NGC MS-67.  Ex - Andy Hansen - Heritage Numismatic Auctions, Inc.'s "Long Beach Signature Sale", May 31-June 2, 2001, Lot 6620, illustrated, sold for $5,290.00

Recent appearances:
NGC Proof-66 Cameo.  Ex - Heritage Numismatic Auctions, Inc.'s "Long Beach Signature Sale", May 31-June 2, 2001, Lot 6680, illustrated, sold for $3,910.00

PCGS Proof-65.  Ex - Heritage Numismatic Auctions, Inc.'s "Philadelphia 2000 Signature Sale", August 6-7, 2000, Lot 6414, illustrated, sold for $4,312.50

PCGS Proof-65.  Ex - Ira & Larry Goldberg Coins & Collectibles, Inc.'s "The California Sale", October 2-3, 2000, Lot 1836, sold for $5,750.00

PCGS Proof-64.  Ex - Superior Galleries' "The ANA 2001 National Money Show Auction", March 8-9, 2001, Lot 399, plated, sold for $2,875.00

NGC Proof-64.  Ex - Bowers & Merena Galleries' "The Rarities Sale", January 3, 2001, Lot 384, illustrated, sold for $1,955.00

Proof-60.  Ex - Ira & Larry Goldberg Coin & Collectibles' "The Fairchild Family Trust Collection Sale", May 28-30, 2001, Lot 1029, not illustrated, sold for $719.00

Brilliant Proof.  Ex - Stack's "65th Anniversary Sale", October 17-19, 2000, Lot 1210, not plated, sold for $718.75

NGC MS-66.  Ex - Heritage Numismatic Auctions, Inc.'s "Long Beach Signature Sale", May 31-June 2, 2001, Lot 6617, not illustrated, sold for $431.25

PCGS MS-66.  Ex - Heritage Numismatic Auctions, Inc.'s "Long Beach Signature Sale", May 31-June 2, 2001, Lot 6618, not illustrated, sold for $460.00

NGC MS-66.  Ex - Heritage Numismatic Auctions, Inc.'s "Long Beach Signature Sale", May 31-June 2, 2001, Lot 6619, not illustrated, sold for $425.50

NGC MS-66.  Ex - Heritage Numismatic Auctions, Inc.'s "Philadelphia 2000 Signature Sale", August 6-7, 2000, Lot 6386, not illustrated, not sold

PCGS MS-66.  Ex- Heritage Numismatic Auctions, Inc.'s "October 2000 Long Beach Sale" October 5-7, 2000, Lot 8450, not illustrated, sold for $747.50

PCGS MS-66.  Ex - Bowers & Merena Galleries' "The Rarities Sale", January 3, 2001, Lot 385, not illustrated, sold for $483.00

NGC MS-63PL, Choice Brilliant Uncirculated.  Ex - Stack's "65th Anniversary Sale", October 17-19, 2000, Lot 1415, not plated, sold for $51.75

Notes:
The finest Uncirculated examples graded by PCGS are 8 MS-67's, 3 MS-67 Prooflikes, and 2 MS-65 Deep Mirror Prooflikes.

Gem Proofs of this date are available for a price, but in PR-66 and better grades, the 1900 Morgan Silver Dollar becomes quite rare.  This is one of the dates that is not available in PR-68 (at least, not in a PCGS holder); the finest Proofs graded by PCGS are 2 PR-67s, a single PRCA-67 Proof Cameo, and 2 PRDC-67 Proof Deep Cameos. 

Sources and/or recommended reading:
"The PCGS Population Report, April 2003" by The Professional Coin Grading Service